Process for the decomposition of a complex of orthobenzoyl-benzoic acid, hydrogen fluoride and boron trifluoride

Abstract

Process for the decomposition of complexes of orthobenzoyl-benzoic acid, hydrogen fluoride, and boron trifluoride in which the complex is subjected to the action of sulfuric acid in a concentration of at least about 96% by weight or to the action of an oleum, under atmospheric pressure or under a pressure lower than atmospheric pressure.

What is claimed is: 
     
       1. Process for the decomposition of complexes of orthobenzoyl-benzoic acid, hydrogen fluoride and boron trifluoride of the general formula: ##STR2## in which n and m are between 1 and 6 on the one hand for recovery of the hydrogen fluoride and the boron trifluoride, and, on the other hand, to obtain the anthraquinone resulting from cyclization of the orthobenzoyl-benzoic acid, the improvement comprising subjecting the said complex to the action of sulfuric acid in a concentration of at least about 96% by weight or of an oleum, under a pressure at most equal to atmospheric pressure and at a temperature between 100° C. and 180° C. 
     
     
       2. The process of claim 1, wherein the amount by weight of sulfuric acid is equal to 1 to 3 times that of the orthobenzoyl-benzoic acid contained in the complex. 
     
     
       3. The process of claim 1, wherein the amount by weight of oleum is equal to 0.5 to 2 times that of the orthobenzoyl-benzoic acid contained in the complex. 
     
     
       4. The process of claim 1, wherein the duration of the decomposition is between 15 minutes and 2 hours. 
     
     
       5. The process of claim 4, wherein the decomposition takes place in the presence of an amount of boric acid sufficient to convert at least some of the hydrogen fluoride contained in the complex into boron trifluoride. 
     
     
       6. The process of claim 5, wherein the final reaction mixture is diluted with water or an aqueous solution of sulfuric acid to precipitate the anthraquinone. 
     
     
       7. The process of claim 1, wherein the amount by weight of sulfuric acid is equal to 1 to 3 times that of the orthobenzoyl-benzoic acid contained in the complex and the duration of the decomposition is between 15 minutes and 2 hours. 
     
     
       8. The process of claim 1, wherein the amount by weight of oleum is equal to 0.5 to 2 times that of the orthobenzoyl-benzoic acid contained in the complex and the duration of the decomposition is between 15 minutes and 2 hours. 
     
     
       9. The process of claim 1, wherein the amount by weight of sulfuric acid is equal to 1 to 3 times that of the orthobenzoyl-benzoic acid contained in the complex, the duration of the decomposition is between 15 minutes and 2 hours, and the decomposition takes place in the presence of an amount of boric acid sufficient to convert at least some of the hydrogen fluoride contained in the complex into boron trifluoride. 
     
     
       10. The process of claim 1, wherein the amount by weight of oleum is equal to 0.5 to 2 times that of the orthobenzoyl-benzoic acid contained in the complex, the duration of the decomposition is between 15 minutes and 2 hours, and the decomposition takes place in the presence of an amount of boric acid sufficient to convert at least some of the hydrogen fluoride contained in the complex into boron trifluoride.